Portable Device for Collecting Particles and Microorganisms

ABSTRACT

The invention relates to a device ( 7 ) for collecting particles and microorganisms present in ambient air, the device comprising a cyclone enclosure ( 8 ) for centrifuging air, the enclosure being of conical or frustoconical shape, external air inlet means ( 16 ) for admitting air into the enclosure ( 8 ), and air outlet means connected by coupling means ( 19, 20, 21 ) to air inlet filter means ( 4 ) of an individual motorized respiratory protection appliance (A).

The present invention relates to a portable device for collecting particles and microorganisms present in ambient air, for purposes of identifying and counting such particles and microorganisms.

Such identification and counting are important in numerous fields such as the pharmaceutical industry, the agri-food industry, medical premises, hygiene services, veterinary services, site surveillance, etc; with the dimensions of the particles and microorganisms that are to be collected lying in the range 0.5 micrometers (μm) to several tens of micrometers.

Devices of this type are known from document FR-A-2 855 831 or from document FR 2 905 379 in the name of the Applicant, which devices comprise a removable centrifuging enclosure containing a collection liquid and associated with air suction means. The enclosure has an air inlet and an air outlet, and it forms a container for transporting a liquid sample containing the collected particles and microorganisms.

Those devices are self-contained, and although they are portable, they are nevertheless relatively bulky. In operation, the flow rate of air passing through the enclosure is relatively large, i.e. greater than 100 liters per minute (L/min). The air flow rate is a function of the application, and in general it is determined so as to take reliable and representative samples in a few minutes.

People who are to move about in a contaminated atmosphere or who are confronted with nuclear, biological, and/or chemical risks are required to wear respiratory protection appliances that may be fitted with filter means for purifying ambient air by filtering it.

Such appliances may be free ventilation appliances, with air passing through the filters solely as a result of the user breathing, or they may be assisted ventilation appliances with the ambient air being sucked in through filters with the help of motorized means.

Known respiratory appliances are not suitable for analyzing the atmosphere in which the users have been moving. When it is desired to perform such an analysis, the user must carry a dedicated collector device, of the type described in the above-mentioned documents FR-A-2 855 831 and FR 2 905 379, and make the device operate in situ, which is not always possible in certain contexts.

A particular object of the invention is to provide a solution to that problem that is simple, effective, and inexpensive.

To this end, the invention provides a portable collector device for collecting particles and microorganisms present in ambient air, the device comprising a cyclone enclosure for centrifuging air, the enclosure being of conical or frustoconical shape, external air inlet means for admitting air into the enclosure, and air outlet means for discharging air from the enclosure, the device being characterized in that it includes coupling means for coupling the air outlet means of the enclosure to air inlet means of an individual motorized respiratory protection appliance.

The collector device of the invention can thus be associated with a respiratory protection appliance in such a manner as to enable particles and microorganisms to be collected continuously throughout the mission of the user, and throughout the duration for which the respiratory protection appliance is in operation.

Advantageously, the coupling means for coupling to the air outlet of the enclosure comprise connection means for connecting to at least one inlet filter of the respiratory protection appliance.

The connection means may comprise at least one endpiece for engaging on the inlet filter of the appliance.

The collector device may then be fitted to and removed from the filter very easily.

According to another characteristic of the invention, the inside surface of the cyclone enclosure is constituted by or covered in an electrostatic material or a material based on nanofibers for collecting the particles or the microorganisms.

By way of example, this material may be an “electret”, which is a dielectric material presenting a quasi permanent state of polarization.

In conventional manner, the external air inlet means lead tangentially into the top portion of the enclosure and the air outlet means lead axially into the top portion of the enclosure.

In a preferred embodiment of the invention, the top portion of the enclosure has a diameter lying in the range 10 millimeters (mm) to 50 mm, and the height or axial dimension of the enclosure lies in the range 10 mm to 100 mm.

The invention also provides an individual motorized respiratory protection appliance including a mask, for being worn by a user, and motorized air feed means, e.g. a turbine, enabling external air to be sucked through at least one filter for retaining the particles or the microorganisms present in the external air, the appliance being characterized in that a collector device of the above specified type is mounted on the filter, upstream therefrom in the external air suction direction.

Advantageously, the air feed means, the filter, and the collector device are dimensioned to supply the user with a continuous flow rate of air that is less than 100 L/min, corresponding to the user's breathing requirements.

Preferably, the appliance is designed to be carried and used for continuous periods of time that may reach approximately 8 hours (h) to 10 h, with particles and microorganisms from external air being collected continuously and while dry inside the cyclone enclosure of the above-mentioned device throughout the duration the respiratory protection appliance is in use.

In a variant, the collector device of the invention can be connected to the air inlet of a motor-driven suction turbine powered by electric batteries, the assembly being designed to be worn by a person and to operate continuously for a duration of several hours, e.g. for about half a day.

The invention also provides a method of collecting and assaying particles and microorganisms present in ambient air, the method being characterized in that, after using the above-specified respiratory protection appliance, it consists in disassembling the cyclone enclosure, in rinsing its inside surface with an appropriate liquid in order to recover the particles and/or the microorganisms collected on said surface, and in analyzing and/or assaying the content of the liquid sample as obtained in this way.

The method may also consist in subjecting the enclosure to ultrasound, after or during rinsing thereof, so as to separate the particles and/or the microorganisms from its inside surface.

The invention can be better understood and other details, characteristics, and advantages of the invention appear on reading the following description made by way of nonlimiting example and with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic view showing a person wearing a prior art individual motorized appliance for respiratory protection;

FIG. 2 is a perspective view of a respiratory protection appliance of the invention;

FIG. 3 is a perspective view of a collector device of the invention;

FIG. 4 is an axial section view of a cyclonic enclosure for centrifuging air; and

FIG. 5 is a perspective view of a variant embodiment of the invention.

FIG. 1 shows a person wearing a jacket 1 having its back fitted with an individual motorized appliance A for respiratory protection that includes a mask (not shown) connected by a pipe 2 to motorized air feed means 3, e.g. to a turbine, enabling outside air to be sucked in through two filters 4 that are to retain particles or microorganisms present in the surrounding atmosphere.

Each filter 4 is generally cylindrical in shape and includes a central air inlet 5 situated in its rear face.

The appliance A is fitted with control means 6 enabling the motorized air feed means 3 to be switched on or off, and enabling the flow rate of air fed to the mask to be adjusted.

As shown in FIG. 2, the invention proposes fitting such an appliance with a collector or device 7 for collecting particles and microorganisms that are present in ambient air.

The device 7 comprises a cyclone enclosure 8 for centrifuging air, which enclosure is of conical or frustoconical shape, and its structure can be seen more clearly in FIG. 4.

In its bottom portion, the enclosure 8 is defined by a first part 9 of generally frustoconical or conical shape with an inside surface 10 that is covered in an electrostatic material, e.g. a material of the “electret” type, or a material based on nanofibers, for the purpose of collecting particles or microorganisms. The top diameter of the first part 9 lies in the range 10 mm to 50 mm, and its height h lies in the range 10 mm to 100 mm. The top end of the first part 9 is provided with an annular rim 11 extending radially outwards.

In its top portion, the enclosure 8 is also defined by a second part 12 on top of the first, comprising a cylindrical outer wall 13 and an axial tube 14 co-operating with the outer wall to define an annular air inlet channel 15 leading into the enclosure. The outer wall 13 includes at least one opening 16 leading tangentially into the annular channel 15, so as to form an air inlet into the top portion of the enclosure 8. The bottom end of the second part 12 is provided with an external thread.

The two parts 9 and 12 are fastened together by means of a ring 17 that is mounted on the rim 11 of the first part 9 by crimping or by snap fastening and that is screwed onto the thread of the second part 12.

The axial tube 14 forms an air outlet leading at its bottom end into the enclosure, and connected at its top end to a coupling that can be seen in FIGS. 2 and 3. This coupling 19 is generally T-shaped, with one branch connected to the air outlet 14 of the enclosure 8 and with its other two branches connected to the two filters 4 via bent pipes 20 and assembly endpieces 21. The coupling 19 is fastened, e.g. by screw fastening, to the second part 12 of the cyclone enclosure 8.

The endpieces 21 are cylindrical and form bells that can be engaged directly on the filters 4. More particularly, each endpiece 21 may be made of an elastomer material and may include a central air outlet 22 (FIG. 3) situated in register with the central air inlet 5 of a respective filter 4.

During operation of the respiratory appliance A, the air as sucked in by the motorized means 3 enters via the inlet 16 of the cyclone enclosure 8 and swirls within the enclosure so that the particles and microorganisms present in the ambient air are centrifuged against the electrostatic material or against the material based on nanofibers covering the inside surface 10 of the part 9.

Unlike the above-mentioned prior art, the enclosure 8 operates while dry, i.e. without any liquid being contained in or injected into the enclosure.

In a variant, even though it is not as effective, collection may also be performed in an enclosure 8 that does not have electrostatic material on its inside surface 10.

The air then leaves the enclosure via the outlet 14, passes along the pipes 20, and then through the filters 4 for in order to be purified before reaching the mask. The air flow rate necessary for proper ventilation of the user is less than 100 L/min, even when the user is exerting relatively intense physical effort. The motorized feed means 3 and the cyclone enclosure 8 are of the dimensions that make such a flow rate possible.

After the user has completed a mission, the user stops the motorized feed means 3 of the respiratory protection appliance, and the enclosure 8 can be disassembled. The first part 9 is rinsed using an appropriate liquid in order to recover the particles and/or the microorganisms collected on the inside surface 10 in the form of a liquid sample that can be analyzed and/or assayed using conventional techniques. In this way, the particles or the microorganisms present in the sample can be identified and counted.

In order to improve separation of the particles or the microorganisms, the first part 9 may be subjected to ultrasound, after or during rinsing.

The invention enables particles or microorganisms to be collected continuously and effectively throughout a mission that may have a duration of as long as 10 h.

The contact or device 7, and more particularly the cyclone enclosure 8 may be designed in such a manner as to enable the respiratory protection appliance 2 to operate even in the event of the motorized feed means 3 stopping, merely by the wearer breathing in air. The head losses created by the collector device 7 must therefore be a small enough to make that possible. Otherwise, the collector device 7 of the invention may be fitted with quick disconnection means enabling ambient air to be breathed directly through the filters 4, without passing via the cyclone enclosure 8. The filters 4 are designed to generate head losses that are small enough to enable the appliance 2 to operate in the event of the motorized feed means 3 failing.

FIG. 5 shows a variant embodiment of a device 7 for collecting particles and microorganisms. In this device 7, the air outlet from the enclosure 8 is connected to the air inlet of a suction turbine having an electric motor that is received in a housing 23 and that is powered by batteries that are themselves received in a housing 24. The housings 23 and 24 may be contiguous or they may be spaced apart from each other. The air outlet from the turbine leads to the outside at 25, in the top portion of the housing 24.

The device 7 is designed to be worn by a person and to operate continuously for a duration of several hours. 

1. A portable collector device for collecting particles and microorganisms present in ambient air, the device comprising a cyclone enclosure for centrifuging air, the enclosure being of conical or frustoconical shape, external air inlet means for admitting air into the enclosure, and air outlet means for discharging air from the enclosure wherein the device further includes coupling means for coupling the air outlet means of the enclosure to air inlet means of an individual motorized respiratory protection appliance.
 2. A device according to claim 1, wherein the coupling means for coupling to the air outlet of the enclosure comprise connection means for connecting to at least one inlet filter of the respiratory protection appliance.
 3. A device according to claim 2, wherein the connection means comprise at least one endpiece for engaging on the inlet filter of the appliance.
 4. A device according to claim 1, wherein the inside surface of the cyclone enclosure is constituted by or covered in an electrostatic material or a material based on nanofibers for collecting the particles or the microorganisms.
 5. A device according to claim 1, wherein the external air inlet means lead tangentially into the top portion of the enclosure and the air outlet means lead axially into the top portion of the enclosure.
 6. A device according to claim 1, wherein the top portion of the enclosure has a diameter lying in the range 10 mm to 50 mm.
 7. A device according to claim 5, wherein the height or axial dimension of the enclosure lies in the range 10 mm to 100 mm.
 8. A device according to claim 1, wherein the air outlet of the enclosure can also be connected to the air inlet of a motor-driven suction turbine powered by batteries, the assembly being designed to be worn by a person and to operate continuously for a duration of several hours.
 9. An individual motorized respiratory protection appliance including a mask, for being worn by a user, and motorized air feed means, enabling external air to be sucked through at least one filter for retaining the particles or the microorganisms present in the external air, wherein the appliance includes that a collector device according to claim 1 is mounted on the filter, upstream therefrom in the external air suction direction.
 10. An appliance according to claim 7, wherein the air feed means, the filter, and the collector device are dimensioned to supply the user with a continuous flow rate of air that is less than 100 L/min.
 11. An appliance according to claim 8, wherein the appliance is configured to be carried and used for continuous periods of time that may reach approximately 8 h to 10 h, and that particles and microorganisms from external air are collected continuously and while dry inside the cyclone enclosure of the above-mentioned device throughout the duration the respiratory protection appliance is in use.
 12. A method of collecting and assaying particles and microorganisms present in ambient air, wherein after using the respiratory protection appliance according to claim 8, the method comprises disassembling the cyclone enclosure, in rinsing an inside surface with an appropriate liquid in order to recover the particles and/or the microorganisms collected on said surface, and in analyzing and/or assaying the content of the sample as produced in this way.
 13. A method according to claim 11, wherein the method further includes subjecting the enclosure to ultrasound, after or during rinsing thereof, so as to separate the particles and/or the microorganisms from its inside surface. 